Vacuum adiabatic body and refrigerator

ABSTRACT

A vacuum adiabatic body includes a first plate; a second plate; a seal; a support; and an exhaust port, wherein an extension tab extending toward the third space to be coupled to the support is provided to at least one of the first and second plates, and the extension tab extends downward from an edge portion of the at least one of the first and second plates.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a U.S. National Stage Application under 35 U.S.C. §371 of PCT Application No. PCT/KR2016/008512, filed Aug. 2, 2016, whichclaims priority to Korean Patent Application Nos. 10-2015-0109622,10-2015-0109626, and 10-2015-0109721, all filed Aug. 3, 2015, whoseentire disclosures are hereby incorporated by reference.

U.S. application Ser. Nos. 15/749,132; 15/749,139; 15/749,136;15/749,143; 15/749,146; 15/749,156; 15/749,162; 15/749,140; 15/749,142;15/749,147; 15/749,149; 15/749,179; 15/749,154; 15/749,161, all filed onJan. 31, 2018, are related and are hereby incorporated by reference intheir entirety. Further, one of ordinary skill in the art will recognizethat features disclosed in these above-noted applications may becombined in any combination with features disclosed herein.

TECHNICAL FIELD

The present disclosure relates to a vacuum adiabatic body and arefrigerator.

BACKGROUND ART

A vacuum adiabatic body is a product for suppressing heat transfer byvacuumizing the interior of a body thereof. The vacuum adiabatic bodycan reduce heat transfer by convection and conduction, and hence isapplied to heating apparatuses and refrigerating apparatuses. In atypical adiabatic method applied to a refrigerator, although it isdifferently applied in refrigeration and freezing, a foam urethaneadiabatic wall having a thickness of about 30 cm or more is generallyprovided. However, the internal volume of the refrigerator is thereforereduced. In order to increase the internal volume of a refrigerator,there is an attempt to apply a vacuum adiabatic body to therefrigerator.

First, Korean Patent No. 10-0343719 (Reference Document 1) of thepresent applicant has been disclosed. According to Reference Document 1,there is disclosed a method in which a vacuum adiabatic panel isprepared and then built in walls of a refrigerator, and the exterior ofthe vacuum adiabatic panel is finished with a separate molding such asStyrofoam (polystyrene). According to the method, additional foaming isnot required, and the adiabatic performance of the refrigerator isimproved. However, manufacturing cost is increased, and a manufacturingmethod is complicated.

As another example, a technique of providing walls using a vacuumadiabatic material and additionally providing adiabatic walls using afoam filling material has been disclosed in Korean Patent PublicationNo. 10-2015-0012712 (Reference Document 2). According to ReferenceDocument 2, manufacturing cost is increased, and a manufacturing methodis complicated.

As another example, there is an attempt to manufacture all walls of arefrigerator using a vacuum adiabatic body that is a single product. Forexample, a technique of providing an adiabatic structure of arefrigerator to be in a vacuum state has been disclosed in U.S. PatentLaid-Open Publication No. US 2004/0226956 A1 (Reference Document 3).

However, it is difficult to obtain an adiabatic effect of a practicallevel by providing the walls of the refrigerator to be in a sufficientvacuum state. Specifically, it is difficult to prevent heat transfer ata contact portion between external and internal cases having differenttemperatures. Further, it is difficult to maintain a stable vacuumstate. Furthermore, it is difficult to prevent deformation of the casesdue to a sound pressure in the vacuum state. Due to these problems, thetechnique of Reference Document 3 is limited to cryogenic refrigeratingapparatuses, and is not applied to refrigerating apparatuses used ingeneral households.

DISCLOSURE Technical Problem

Embodiments provide a vacuum adiabatic body and a refrigerator, whichcan obtain a sufficient adiabatic effect in a vacuum state and beapplied commercially. Embodiments also provide a structure for improvingthe supporting ability of a plate member provided in a vacuum adiabaticbody. Embodiments also provide a vacuum adiabatic body of which at leastone portion forms a curved surface and a refrigerator including thesame.

Technical Solution

In one embodiment, a vacuum adiabatic body includes: a first platemember defining at least one portion of a wall for a first space; asecond plate member defining at least one portion of a wall for a secondspace having a different temperature from the first space; a sealingpart sealing the first plate member and the second plate member toprovide a third space that has a temperature between the temperature ofthe first space and the temperature of the second space and is in avacuum state; a supporting unit maintaining the third space; a heatresistance unit for decreasing a heat transfer amount between the firstplate member and the second plate member; and an exhaust port throughwhich a gas in the third space is exhausted, wherein an extending partextending toward the third space to be coupled to the supporting unit isprovided to at least one of the first and second plate members, and theextending part is formed to extend downward from an edge portion of theat least one of the first and second plate members.

In another embodiment, a vacuum adiabatic body includes: a first platemember defining at least one portion of a wall for a first space; asecond plate member defining at least one portion of a wall for a secondspace having a different temperature from the first space; a sealingpart sealing the first plate member and the second plate member toprovide a third space that has a temperature between the temperature ofthe first space and the temperature of the second space and is in avacuum state; a supporting unit maintaining the third space; a heatresistance unit for decreasing a heat transfer amount between the firstplate member and the second plate member; and an exhaust port throughwhich a gas in the third space is exhausted, wherein the supporting unitincludes support plates respectively contacting the first and secondplate members, and each of the first and second plate members and thesupport plates is provided as a curved surface, and is formed such thatits curvature is increased as it is distant from the center ofcurvature.

In still another embodiment, a vacuum adiabatic body includes: a firstplate member defining at least one portion of a wall for a first space;a second plate member defining at least one portion of a wall for asecond space having a different temperature from the first space; asealing part sealing the first plate member and the second plate memberto provide a third space that has a temperature between the temperatureof the first space and the temperature of the second space and is in avacuum state; a supporting unit maintaining the third space; a heatresistance unit including at least one radiation resistance sheetprovided in a plate shape inside the third space to decrease a heattransfer amount between the first plate member and the second platemember; and an exhaust port through which a gas in the third space isexhausted, wherein the radiation resistance sheet is provided with atleast one first hole having a small diameter and at least one secondhole having a large diameter, so that bars of the supporting unit areinserted into the first and second holes, and a number of the firstholes is smaller than that of the second holes.

In still another embodiment, a refrigerator includes: a main bodyprovided with an internal space in which storage goods are stored; and adoor provided to open/close the main body from an external space,wherein, in order to supply a refrigerant into the main body, therefrigerator includes: a compressor for compressing the refrigerant; acondenser for condensing the compressed refrigerant; an expander forexpanding the condensed refrigerant; and an evaporator for evaporatingthe expanded refrigerant to take heat, wherein at least one of the mainbody and the door includes a vacuum adiabatic body, wherein the vacuumadiabatic body includes: a first plate member defining at least oneportion of a wall for the internal space; a second plate member definingat least one portion of a wall for the external space; a sealing partsealing the first plate member and the second plate member to provide avacuum space part that has a temperature between a temperature of theinternal space and a temperature of the external space and is in avacuum state; a supporting unit maintaining the vacuum space part; aheat resistance unit connected to at least one of the first and secondplate members, the heat resistance unit decreasing a heat transferamount between the first plate member and the second plate member; andan exhaust port through which a gas in the vacuum space part isexhausted, wherein at least one of the first and second plate members isprovided with an extending part extending toward the vacuum space part,the extending part being coupled to the supporting unit.

Advantageous Effects

According to the present disclosure, it is possible to provide a vacuumadiabatic body having a vacuum adiabatic effect and a refrigeratorincluding the same. Also, the vacuum adiabatic body of the presentdisclosure can effectively overcome radiation heat transfer of thevacuum space part. According to the present disclosure, it is possibleto sufficiently resist heat transfer through a structure for resistingradiation heat transfer.

Also, it is possible to improve the supporting ability of the platemember using the supporting unit. Also, components constituting thevacuum adiabatic body are not formed to have curved surfaces throughinjection molding, but formed by changing only an assembling process, sothat it is possible to manufacture a vacuum adiabatic body formed in acurved shape.

DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view of a refrigerator according to anembodiment.

FIG. 2 is a view schematically showing a main body of the refrigeratorand a vacuum adiabatic body according to an embodiment.

FIG. 3 is a view showing various embodiments of an internalconfiguration of a vacuum space part.

FIG. 4 is a view showing various embodiments of conductive resistancesheets and peripheral parts thereof.

FIG. 5 is a view showing in detail a vacuum adiabatic body according toa second embodiment.

FIG. 6 is view showing a state in which a radiation resistance sheet isfastened to a supporting unit of FIG. 5.

FIG. 7 is a sectional view taken along line I-I′ of FIG. 6.

FIG. 8 is a sectional view taken along line II-II′ of FIG. 6.

FIG. 9 is a plan view of one vertex portion of the radiation resistancesheet of FIG. 5.

FIG. 10 illustrates graphs showing changes in adiabatic performance andchanges in gas conductivity with respect to vacuum pressures by applyinga simulation.

FIG. 11 illustrates graphs obtained by observing, over time andpressure, a process of exhausting the interior of the vacuum adiabaticbody when a supporting unit is used.

FIG. 12 illustrates graphs obtained by comparing vacuum pressures andgas conductivities.

FIG. 13 is a view illustrating a correlation between a supporting unitand a first plate member of a vacuum adiabatic body according to a thirdembodiment, which shows any one edge portion.

FIG. 14 is an enlarged view of FIG. 13.

FIG. 15 is a longitudinal sectional view of FIG. 13.

FIG. 16 is a view showing the supporting unit and a radiation resistancesheet of FIG. 13.

FIG. 17 is a plan view of FIG. 16.

FIG. 18 is a view showing a vacuum adiabatic body according to a fourthembodiment.

FIG. 19 is a view showing a first plate member of FIG. 18.

FIG. 20 is a view showing a vacuum adiabatic body according to a fifthembodiment.

FIG. 21 is a view showing a vacuum adiabatic body according to a sixthembodiment.

FIG. 22 is a longitudinal sectional view of FIG. 21.

FIG. 23 is a view showing a vacuum adiabatic body according to a seventhembodiment.

FIG. 24 is a view showing a supporting unit of FIG. 23.

FIG. 25 is an exploded view of the supporting unit of FIG. 23.

FIG. 26 is a view showing a case where a plurality of radiationresistance sheets are provided in the supporting unit of FIG. 23.

FIG. 27 is a view showing the supporting unit of FIG. 23, viewed fromthe top.

FIG. 28 is a view showing a side of the supporting unit of FIG. 23.

FIG. 29 is a view showing an edge portion of a support plate of FIG. 23.

MODE FOR INVENTION

Reference will now be made in detail to the embodiments of the presentdisclosure, examples of which are illustrated in the accompanyingdrawings.

In the following detailed description of the preferred embodiments,reference is made to the accompanying drawings that form a part hereof,and in which is shown by way of illustration specific preferredembodiments in which the disclosure may be practiced. These embodimentsare described in sufficient detail to enable those skilled in the art topractice the disclosure, and it is understood that other embodiments maybe utilized and that logical structural, mechanical, electrical, andchemical changes may be made without departing from the spirit or scopeof the disclosure. To avoid detail not necessary to enable those skilledin the art to practice the disclosure, the description may omit certaininformation known to those skilled in the art. The following detaileddescription is, therefore, not to be taken in a limiting sense.

In the following description, the term ‘vacuum pressure’ means a certainpressure state lower than atmospheric pressure. In addition, theexpression that a vacuum degree of A is higher than that of B means thata vacuum pressure of A is lower than that of B.

FIG. 1 is a perspective view of a refrigerator according to anembodiment. FIG. 2 is a view schematically showing a main body of therefrigerator and a vacuum adiabatic body according to an embodiment. InFIG. 2, a main body-side vacuum adiabatic body is illustrated in a statein which top and side walls are removed, and a door-side vacuumadiabatic body is illustrated in a state in which a portion of a frontwall is removed. In addition, sections of portions at conductiveresistance sheets are provided are schematically illustrated forconvenience of understanding.

Referring to FIGS. 1 and 2, the refrigerator 1 includes a main body 2provided with a cavity 9 capable of storing storage goods and a door 3provided to open/close the main body 2. The door 3 may be rotatably ormovably disposed to open/close the cavity 9. The cavity 9 may provide atleast one of a refrigerating chamber and a freezing chamber.

Parts constituting a freezing cycle in which cold air is supplied intothe cavity 9 may be included. Specifically, the parts include acompressor 4 for compressing a refrigerant, a condenser 5 for condensingthe compressed refrigerant, an expander 6 for expanding the condensedrefrigerant, and an evaporator 7 for evaporating the expandedrefrigerant to take heat. As a typical structure, a fan may be installedat a position adjacent to the evaporator 7, and a fluid blown from thefan may pass through the evaporator 7 and then be blown into the cavity9. A freezing load is controlled by adjusting the blowing amount andblowing direction by the fan, adjusting the amount of a circulatedrefrigerant, or adjusting the compression rate of the compressor, sothat it is possible to control a refrigerating space or a freezingspace.

The vacuum adiabatic body includes a first plate member (or first plate)10 for providing a wall of a low-temperature space, a second platemember (or second plate) 20 for providing a wall of a high-temperaturespace, and a vacuum space part (or vacuum space) 50 defined as a gappart between the first and second plate members 10 and 20. Also, thevacuum adiabatic body includes the conductive resistance sheets 60 and62 for preventing heat conduction between the first and second platemembers 10 and 20.

A sealing part (or seal) 61 for sealing the first and second platemembers 10 and 20 is provided such that the vacuum space part 50 is in asealing state. When the vacuum adiabatic body is applied to arefrigerating or heating cabinet, the first plate member 10 may bereferred to as an inner case, and the second plate member 20 may bereferred to as an outer case. A machine chamber 8 in which partsproviding a freezing cycle are accommodated is placed at a lower rearside of the main body-side vacuum adiabatic body, and an exhaust port 40for forming a vacuum state by exhausting air in the vacuum space part 50is provided at any one side of the vacuum adiabatic body. In addition, apipeline 64 passing through the vacuum space part 50 may be furtherinstalled so as to install a defrosting water line and electric lines.

The first plate member 10 may define at least one portion of a wall fora first space provided thereto. The second plate member 20 may define atleast one portion of a wall for a second space provided thereto. Thefirst space and the second space may be defined as spaces havingdifferent temperatures. Here, the wall for each space may serve as notonly a wall directly contacting the space but also a wall not contactingthe space. For example, the vacuum adiabatic body of the embodiment mayalso be applied to a product further having a separate wall contactingeach space.

Factors of heat transfer, which cause loss of the adiabatic effect ofthe vacuum adiabatic body, are heat conduction between the first andsecond plate members 10 and 20, heat radiation between the first andsecond plate members 10 and 20, and gas conduction of the vacuum spacepart 50.

Hereinafter, a heat resistance unit provided to reduce adiabatic lossrelated to the factors of the heat transfer will be provided. Meanwhile,the vacuum adiabatic body and the refrigerator of the embodiment do notexclude that another adiabatic means is further provided to at least oneside of the vacuum adiabatic body. Therefore, an adiabatic means usingfoaming or the like may be further provided to another side of thevacuum adiabatic body.

FIG. 3 is a view showing various embodiments of an internalconfiguration of the vacuum space part. First, referring to FIG. 3a ,the vacuum space part 50 is provided in a third space having a differentpressure from the first and second spaces, preferably, a vacuum state,thereby reducing adiabatic loss. The third space may be provided at atemperature between the temperature of the first space and thetemperature of the second space. Since the third space is provided as aspace in the vacuum state, the first and second plate members 10 and 20receive a force contracting in a direction in which they approach eachother due to a force corresponding to a pressure difference between thefirst and second spaces. Therefore, the vacuum space part 50 may bedeformed in a direction in which it is reduced. In this case, adiabaticloss may be caused due to an increase in amount of heat radiation,caused by the contraction of the vacuum space part 50, and an increasein amount of heat conduction, caused by contact between the platemembers 10 and 20.

A supporting unit (or support) 30 may be provided to reduce thedeformation of the vacuum space part 50. The supporting unit 30 includesbars 31. The bars 31 may extend in a direction substantially vertical tothe first and second plate members 10 and 20 so as to support a distancebetween the first and second plate members 10 and 20. A support plate 35may be additionally provided to at least one end of the bar 31. Thesupport plate 35 connects at least two bars 31 to each other, and mayextend in a direction horizontal to the first and second plate members10 and 20.

The support plate 35 may be provided in a plate shape, or may beprovided in a lattice shape such that its area contacting the first orsecond plate member 10 or 20 is decreased, thereby reducing heattransfer. The bars 31 and the support plate 35 are fixed to each otherat at least one portion, to be inserted together between the first andsecond plate members 10 and 20. The support plate 35 contacts at leastone of the first and second plate members 10 and 20, thereby preventingdeformation of the first and second plate members 10 and 20.

In addition, based on the extending direction of the bars 31, a totalsectional area of the support plate 35 is provided to be greater thanthat of the bars 31, so that heat transferred through the bars 31 can bediffused through the support plate 35. A material of the supporting unit30 may include a resin selected from the group consisting of PC, glassfiber PC, low outgassing PC, PPS, and LCP so as to obtain highcompressive strength, low outgassing and water absorptance, low thermalconductivity, high compressive strength at high temperature, andexcellent machinability.

A radiation resistance sheet 32 for reducing heat radiation between thefirst and second plate members 10 and 20 through the vacuum space part50 will be described. The first and second plate members 10 and 20 maybe made of a stainless material capable of preventing corrosion andproviding a sufficient strength. The stainless material has a relativelyhigh emissivity of 0.16, and hence a large amount of radiation heat maybe transferred.

In addition, the supporting unit 30 made of the resin has a loweremissivity than the plate members, and is not entirely provided to innersurfaces of the first and second plate members 10 and 20. Hence, thesupporting unit 30 does not have great influence on radiation heat.Therefore, the radiation resistance sheet 32 may be provided in a plateshape over a majority of the area of the vacuum space part 50 so as toconcentrate on reduction of radiation heat transferred between the firstand second plate members 10 and 20.

A product having a low emissivity may be preferably used as the materialof the radiation resistance sheet 32. In an embodiment, an aluminum foilhaving an emissivity of 0.02 may be used as the radiation resistancesheet 32. Since the transfer of radiation heat cannot be sufficientlyblocked using one radiation resistance sheet, at least two radiationresistance sheets 32 may be provided at a certain distance so as not tocontact each other. In addition, at least one radiation resistance sheetmay be provided in a state in which it contacts the inner surface of thefirst or second plate member 10 or 20.

Referring to FIG. 3b , the distance between the plate members ismaintained by the supporting unit 30, and a porous material 33 may befilled in the vacuum space part 50. The porous material 33 may have ahigher emissivity than the stainless material of the first and secondplate members 10 and 20. However, since the porous material 33 is filledin the vacuum space part 50, the porous material 33 has a highefficiency for resisting the radiation heat transfer. In thisembodiment, the vacuum adiabatic body can be manufactured without usingthe radiation resistance sheet 32.

Referring to FIG. 3c , the supporting unit 30 maintaining the vacuumspace part 50 is not provided. Instead of the supporting unit 30, theporous material 33 is provided in a state in which it is surrounded by afilm 34. In this case, the porous material 33 may be provided in a statein which it is compressed so as to maintain the gap of the vacuum spacepart 50. The film 34 is made of, for example, a PE material, and may beprovided in a state in which holes are formed therein.

In this embodiment, the vacuum adiabatic body can be manufacturedwithout using the supporting unit 30. In other words, the porousmaterial 33 can serve together as the radiation resistance sheet 32 andthe supporting unit 30.

FIG. 4 is a view showing various embodiments of the conductiveresistance sheets and peripheral parts thereof. Structures of theconductive resistance sheets are briefly illustrated in FIG. 2, but willbe understood in detail with reference to FIG. 4.

First, a conductive resistance sheet proposed in FIG. 4a may bepreferably applied to the main body-side vacuum adiabatic body.Specifically, the first and second plate members 10 and 20 are to besealed so as to vacuumize the interior of the vacuum adiabatic body. Inthis case, since the two plate members have different temperatures fromeach other, heat transfer may occur between the two plate members. Aconductive resistance sheet 60 is provided to prevent heat conductionbetween two different kinds of plate members.

The conductive resistance sheet 60 may be provided with sealing parts 61at which both ends of the conductive resistance sheet 60 are sealed todefine at least one portion of the wall for the third space and maintainthe vacuum state. The conductive resistance sheet 60 may be provided asa thin foil in units of micrometers so as to reduce the amount of heatconducted along the wall for the third space. The sealing parts 61 maybe provided as welding parts. That is, the conductive resistance sheet60 and the plate members 10 and 20 may be fused to each other.

In order to cause a fusing action between the conductive resistancesheet 60 and the plate members 10 and 20, the conductive resistancesheet 60 and the plate members 10 and 20 may be made of the samematerial, and a stainless material may be used as the material. Thesealing parts 61 are not limited to the welding parts, and may beprovided through a process such as cocking. The conductive resistancesheet 60 may be provided in a curved shape. Thus, a heat conductiondistance of the conductive resistance sheet 60 is provided longer thanthe linear distance of each plate member, so that the amount of heatconduction can be further reduced.

A change in temperature occurs along the conductive resistance sheet 60.Therefore, in order to block heat transfer to the exterior of theconductive resistance sheet 60, a shielding part (or shield) 62 may beprovided at the exterior of the conductive resistance sheet 60 such thatan adiabatic action occurs. In other words, in the refrigerator, thesecond plate member 20 has a high temperature and the first plate member10 has a low temperature. In addition, heat conduction from hightemperature to low temperature occurs in the conductive resistance sheet60, and hence the temperature of the conductive resistance sheet 60 issuddenly changed. Therefore, when the conductive resistance sheet 60 isopened to the exterior thereof, heat transfer through the opened placemay seriously occur.

In order to reduce heat loss, the shielding part 62 is provided at theexterior of the conductive resistance sheet 60. For example, when theconductive resistance sheet 60 is exposed to any one of thelow-temperature space and the high-temperature space, the conductiveresistance sheet 60 does not serve as a conductive resistor as well asthe exposed portion thereof, which is not preferable.

The shielding part 62 may be provided as a porous material contacting anouter surface of the conductive resistance sheet 60. The shielding part62 may be provided as an adiabatic structure, e.g., a separate gasket,which is placed at the exterior of the conductive resistance sheet 60.The shielding part 62 may be provided as a portion of the vacuumadiabatic body, which is provided at a position facing a correspondingconductive resistance sheet 60 when the main body-side vacuum adiabaticbody is closed with respect to the door-side vacuum adiabatic body. Inorder to reduce heat loss even when the main body and the door areopened, the shielding part 62 may be preferably provided as a porousmaterial or a separate adiabatic structure.

A conductive resistance sheet proposed in FIG. 4b may be preferablyapplied to the door-side vacuum adiabatic body. In FIG. 4b , portionsdifferent from those of FIG. 4a are described in detail, and the samedescription is applied to portions identical to those of FIG. 4a . Aside frame 70 is further provided at an outside of the conductiveresistance sheet 60. A part for sealing between the door and the mainbody, an exhaust port necessary for an exhaust process, a getter portfor vacuum maintenance, and the like may be placed on the side frame 70.This is because the mounting of parts is convenient in the mainbody-side vacuum adiabatic body, but the mounting positions of parts arelimited in the door-side vacuum adiabatic body.

In the door-side vacuum adiabatic body, it is difficult to place theconductive resistance sheet 60 at a front end portion of the vacuumspace part, i.e., a corner side portion of the vacuum space part. Thisis because, unlike the main body, a corner edge portion of the door isexposed to the exterior. More specifically, if the conductive resistancesheet 60 is placed at the front end portion of the vacuum space part,the corner edge portion of the door is exposed to the exterior, andhence there is a disadvantage in that a separate adiabatic part shouldbe configured so as to heat-insulate the conductive resistance sheet 60.

A conductive resistance sheet proposed in FIG. 4c may be preferablyinstalled in the pipeline passing through the vacuum space part. In FIG.4c , portions different from those of FIGS. 4a and 4b are described indetail, and the same description is applied to portions identical tothose of FIGS. 4a and 4b . A conductive resistance sheet having the sameshape as that of FIG. 4a , preferably, a wrinkled conductive resistancesheet 63 may be provided at a peripheral portion of the pipeline 64.Accordingly, a heat transfer path can be lengthened, and deformationcaused by a pressure difference can be prevented. In addition, aseparate shielding part may be provided to improve the adiabaticperformance of the conductive resistance sheet.

A heat transfer path between the first and second plate members 10 and20 will be described with reference back to FIG. 4a . Heat passingthrough the vacuum adiabatic body may be divided into surface conductionheat {circle around (1)} conducted along a surface of the vacuumadiabatic body, more specifically, the conductive resistance sheet 60,supporter conduction heat {circle around (2)} conducted along thesupporting unit 30 provided inside the vacuum adiabatic body, gasconduction heat (or convection) {circle around (3)} conducted through aninternal gas in the vacuum space part, and radiation transfer heat{circle around (4)} transferred through the vacuum space part.

The transfer heat may be changed depending on various design dimensions.For example, the supporting unit may be changed such that the first andsecond plate members 10 and 20 can endure a vacuum pressure withoutbeing deformed, the vacuum pressure may be changed, the distance betweenthe plate members may be changed, and the length of the conductiveresistance sheet may be changed. The transfer heat may be changeddepending on a difference in temperature between the spaces (the firstand second spaces) respectively provided by the plate members. In theembodiment, a preferred configuration of the vacuum adiabatic body hasbeen found by considering that its total heat transfer amount is smallerthan that of a typical adiabatic structure formed by foamingpolyurethane. In a typical refrigerator including the adiabaticstructure formed by foaming the polyurethane, an effective heat transfercoefficient may be proposed as 19.6 mW/mK.

By performing a relative analysis on heat transfer amounts of the vacuumadiabatic body of the embodiment, a heat transfer amount by the gasconduction heat {circle around (3)} can become smallest. For example,the heat transfer amount by the gas conduction heat {circle around (3)}may be controlled to be equal to or smaller than 4% of the total heattransfer amount. A heat transfer amount by solid conduction heat definedas a sum of the surface conduction heat {circle around (1)} and thesupporter conduction heat {circle around (2)} is largest. For example,the heat transfer amount by the solid conduction heat may reach 75% ofthe total heat transfer amount. A heat transfer amount by the radiationtransfer heat {circle around (4)} is smaller than the heat transferamount by the solid conduction heat but larger than the heat transferamount of the gas conduction heat {circle around (3)}. For example, theheat transfer amount by the radiation transfer heat {circle around (4)}may occupy about 20% of the total heat transfer amount.

According to such a heat transfer distribution, effective heat transfercoefficients (eK: effective K) (W/mK) of the surface conduction heat{circle around (1)}, the supporter conduction heat {circle around (2)},the gas conduction heat {circle around (3)}, and the radiation transferheat {circle around (4)} may have an order of Math Figure 1.eK_(solidconductionheat)>eK_(radiationtransferheat)>eK_(gasconductionheat)  [MathFigure 1]

Here, the effective heat transfer coefficient (eK) is a value that canbe measured using a shape and temperature differences of a targetproduct. The effective heat transfer coefficient (eK) is a value thatcan be obtained by measuring a total heat transfer amount and atemperature of at least one portion at which heat is transferred. Forexample, a calorific value (W) is measured using a heating source thatcan be quantitatively measured in the refrigerator, a temperaturedistribution (K) of the door is measured using heats respectivelytransferred through a main body and an edge of the door of therefrigerator, and a path through which heat is transferred is calculatedas a conversion value (m), thereby evaluating an effective heat transfercoefficient.

The effective heat transfer coefficient (eK) of the entire vacuumadiabatic body is a value given by k=QL/AΔT. Here, Q denotes a calorificvalue (W) and may be obtained using a calorific value of a heater. Adenotes a sectional area (m2) of the vacuum adiabatic body, L denotes athickness (m) of the vacuum adiabatic body, and ΔT denotes a temperaturedifference.

For the surface conduction heat, a conductive calorific value may beobtained through a temperature difference (ΔT) between an entrance andan exit of the conductive resistance sheet 60 or 63, a sectional area(A) of the conductive resistance sheet, a length (L) of the conductiveresistance sheet, and a thermal conductivity (k) of the conductiveresistance sheet (the thermal conductivity of the conductive resistancesheet is a material property of a material and can be obtained inadvance). For the supporter conduction heat, a conductive calorificvalue may be obtained through a temperature difference (ΔT) between anentrance and an exit of the supporting unit 30, a sectional area (A) ofthe supporting unit, a length (L) of the supporting unit, and a thermalconductivity (k) of the supporting unit.

Here, the thermal conductivity of the supporting unit is a materialproperty of a material and can be obtained in advance. The sum of thegas conduction heat {circle around (3)}, and the radiation transfer heat{circle around (4)} may be obtained by subtracting the surfaceconduction heat and the supporter conduction heat from the heat transferamount of the entire vacuum adiabatic body. A ratio of the gasconduction heat {circle around (3)}, and the radiation transfer heat{circle around (4)} may be obtained by evaluating radiation transferheat when no gas conduction heat exists by remarkably lowering a vacuumdegree of the vacuum space part 50.

When a porous material is provided inside the vacuum space part 50,porous material conduction heat {circle around (3)} may be a sum of thesupporter conduction heat {circle around (2)} and the radiation transferheat {circle around (4)}. The porous material conduction heat {circlearound (5)} may be changed depending on various variables including akind, an amount, and the like of the porous material.

According to an embodiment, a temperature difference ΔT1 between ageometric center formed by adjacent bars 31 and a point at which each ofthe bars 31 is located may be preferably provided to be less than 0.5°C. Also, a temperature difference ΔT2 between the geometric centerformed by the adjacent bars 31 and an edge portion of the vacuumadiabatic body may be preferably provided to be less than 0.5° C. In thesecond plate member 20, a temperature difference between an averagetemperature of the second plate and a temperature at a point at which aheat transfer path passing through the conductive resistance sheet 60 or63 meets the second plate may be largest.

For example, when the second space is a region hotter than the firstspace, the temperature at the point at which the heat transfer pathpassing through the conductive resistance sheet meets the second platemember becomes lowest. Similarly, when the second space is a regioncolder than the first space, the temperature at the point at which theheat transfer path passing through the conductive resistance sheet meetsthe second plate member becomes highest.

This means that the amount of heat transferred through other pointsexcept the surface conduction heat passing through the conductiveresistance sheet should be controlled, and the entire heat transferamount satisfying the vacuum adiabatic body can be achieved only whenthe surface conduction heat occupies the largest heat transfer amount.To this end, a temperature variation of the conductive resistance sheetmay be controlled to be larger than that of the plate member.

Physical characteristics of the parts constituting the vacuum adiabaticbody will be described. In the vacuum adiabatic body, a force by vacuumpressure is applied to all of the parts. Therefore, a material having astrength (N/m2) of a certain level may be preferably used.

Under such circumferences, the plate members 10 and 20 and the sideframe 70 may be preferably made of a material having a sufficientstrength with which they are not damaged by even vacuum pressure. Forexample, when the number of bars 31 is decreased so as to limit thesupport conduction heat, deformation of the plate member occurs due tothe vacuum pressure, which may be a bad influence on the externalappearance of refrigerator. The radiation resistance sheet 32 may bepreferably made of a material that has a low emissivity and can beeasily subjected to thin film processing. Also, the radiation resistancesheet 32 is to ensure a strength high enough not to be deformed by anexternal impact. The supporting unit 30 is provided with a strength highenough to support the force by the vacuum pressure and endure anexternal impact, and is to have machinability. The conductive resistancesheet 60 may be preferably made of a material that has a thin plateshape and can endure the vacuum pressure.

In an embodiment, the plate member, the side frame, and the conductiveresistance sheet may be made of stainless materials having the samestrength. The radiation resistance sheet may be made of aluminum havinga weaker strength that the stainless materials. The supporting unit maybe made of resin having a weaker strength than the aluminum.

Unlike the strength from the point of view of materials, analysis fromthe point of view of stiffness is required. The stiffness (N/m) is aproperty that would not be easily deformed. Although the same materialis used, its stiffness may be changed depending on its shape. Theconductive resistance sheets 60 or 63 may be made of a material having apredetermined strength, but the stiffness of the material is preferablylow so as to increase heat resistance and minimize radiation heat as theconductive resistance sheet is uniformly spread without any roughnesswhen the vacuum pressure is applied. The radiation resistance sheet 32requires a stiffness of a certain level so as not to contact anotherpart due to deformation. Particularly, an edge portion of the radiationresistance sheet may generate conduction heat due to drooping caused bythe self-load of the radiation resistance sheet. Therefore, a stiffnessof a certain level is required. The supporting unit 30 requires astiffness high enough to endure a compressive stress from the platemember and an external impact.

In an embodiment, the plate member and the side frame may preferablyhave the highest stiffness so as to prevent deformation caused by thevacuum pressure. The supporting unit, particularly, the bar maypreferably have the second highest stiffness. The radiation resistancesheet may preferably have a stiffness that is lower than that of thesupporting unit but higher than that of the conductive resistance sheet.

The conductive resistance sheet may be preferably made of a materialthat is easily deformed by the vacuum pressure and has the loweststiffness. Even when the porous material 33 is filled in the vacuumspace part 50, the conductive resistance sheet may preferably have thelowest stiffness, and the plate member and the side frame may preferablyhave the highest stiffness.

FIG. 5 is a view showing in detail a vacuum adiabatic body according toa second embodiment. The embodiment proposed in FIG. 5 may be preferablyapplied to the door-side vacuum adiabatic body, and the description ofthe vacuum adiabatic body shown in FIG. 4b among the vacuum adiabaticbodies shown in FIG. 4 may be applied to portions to which specificdescriptions are not provided.

Referring to FIG. 5, the vacuum adiabatic body may include a first platemember 10, a second plate member 20, a conductive resistance sheet 60,and a side frame 70, which are parts that enable a vacuum space part 50to be separated from an external atmospheric space. The side frame 70 isformed in a bent shape, and may be provided such that an outer portion,i.e., an edge portion when viewed from the entire shape of the vacuumadiabatic body is lowered. The side frame 70 may be provided in a shapein which a gap part between the side frame 70 and the second platemember 20 is divided into a part having a high height as h1 and a parthaving a low height as h2.

According to the above-described shape, the part at which the height ofthe side frame 70 is low can ensure a predetermined space as comparedwith another part at the exterior of the vacuum adiabatic body. Anadditional mounting part 80 in which an addition such as an exhaust portor a door hinge is mounted may be provided due to a height difference ofthe side frame 70. Accordingly, it is possible to maximally ensure theinternal volume of a product such as the refrigerator provided by thevacuum adiabatic body, to improve an adiabatic effect, and tosufficiently ensure functions of the product.

One end of the side frame 70 is fastened to the conductive resistancesheet 60 by a sealing part 61, and the other end of the side frame 70 isfastened to the second plate member 20 by an edge part (or edge seal)611. The edge part 611 may be provided as a welding part. The vacuumspace part 50 extends up to the edge part 611, thereby improving anadiabatic effect.

The side frame 70 provides a path through which solid conduction heatpassing through the conductive resistance sheet 60 passes. In therefrigerator, cold air passing through the conductive resistance sheet60 may be transferred to the edge part 611 that is a contact pointbetween the side frame 70 and a side part 202 of the second plate member20. However, the cold air may not only be reduced by the conductiveresistance sheet 60 but also sufficiently resist while flowing along theside frame 70.

The second plate member 20 includes a front part (or front face) 201 andthe side part (or side face) 202 bent from the front part 201, and theside part 202 is not exposed to the exterior. Thus, although dew isformed on the side part 202, the dew is not recognized by a user,thereby improving a user's emotion. In addition, when the edge part 611is provided as a welding part, a welding line inevitably generated dueto heating is not viewed from the exterior, thereby improving a user'ssense of beauty. It can be easily assumed that the side part 202 formsan outer wall of the vacuum space part 50.

The edge part 611 may be provided to not only the side part 202 but alsoa corner portion of the front part 201 adjacent to the side part 202,not to be easily observed by the user. As another example, the edge part611 may be provided to an edge portion of the second plate member 20, toenhance convenience of manufacturing while the edge part 611 is notobserved with the naked eye.

In the refrigerator, the cold air passing through the conductiveresistance sheet 60 is transferred to the side frame 70, and hence theside frame 70 has a relatively higher temperature than the first platemember 10. Thus, a temperature of the side frame 70 contacting a secondbar 313 can be maintained higher than that of a place contacting a firstbar 311. Accordingly, although lengths of the first and second bars 311and 313 are different from each other, heat conduction through the firstbar 311 can be maintained equal to that through the second bar 313.According to an experiment, it has been found that a second vacuum spacepart (or second vacuum space) 502 having a height of 1 to 2 mm canobtain a sufficient adiabatic effect equal to that of a first vacuumspace part (or first vacuum space) 501 having a height of 10 to 20 mm.

The vacuum space part 50 includes the first vacuum space part 501 ofwhich height is h1 and the second vacuum space part 502 of which heightis h2 smaller than h1. The first and second vacuum space parts 501 and502 can communicate with each other in a vacuum state. Accordingly, itis possible to reduce inconvenience of a manufacturing process in whicha vacuum space part is separately formed.

A second support plate 352 may be provided to extend inside the secondvacuum space part 502. In addition, the second bar 313 having a lowerheight than the first bar 311 may be provided to the second supportplate 352. Thus, the gap of the second vacuum space part 502 can bemaintained by the second bar 313. The second bar 313 may be provided asa single body with the second support plate 352. Since the heights ofthe first and second vacuum space parts 501 and 502 are different fromeach other, a first support plate 351 may not extend to the secondvacuum space part 502. Although the first support plate 351 does notextend to the second vacuum space part 502, the flow of heat conductedfrom the first plate member 10 to the side frame 70 is resisted by theconductive resistance sheet 60, and thus conduction heat through thesecond bar 313 can obtain an equal effect of heat resistance as comparedwith heat conduction through the first bar 313.

As already described above, the conductive resistance sheet 60 has onepurpose to resist heat transfer from the first plate member 10.Therefore, a rapid change in temperature occurs in the conductiveresistance sheet 60 along the direction of the heat transfer. It hasbeen described that the shielding part 62 is provided to block heattransferred to the outside of the vacuum adiabatic body, correspondingto the rapid change in temperature. Similarly, heat transferred to theinside of the vacuum adiabatic body is provided by the vacuum space part50. The heat can obtain an adiabatic effect with respect to convectionand solid conduction heat, but is weak against heat transfer caused byradiation and gas conduction. In order to solve such a problem, aradiation resistance sheet 32 may be placed even under a lower side ofthe conductive resistance sheet 60.

Specifically, the radiation resistance sheet 32 may include first,second, and third radiation resistance sheets 321, 322, and 323sequentially provided in a direction toward the second support plate 352from the first support plate 351. The first radiation resistance sheet321 may extend up to the lower side of the conductive resistance sheet60 by passing through an end portion of the first support plate 351. Thesecond radiation resistance sheet 322 may extend outward by w2 ascompared with the first radiation resistance sheet 321. The thirdradiation resistance sheet 323 may extend outward by w1 as compared withthe second radiation resistance sheet 322.

According to such a configuration, the radiation resistance sheet 32provided as a thin plate may be deformed by an external impact and load.This is because, if any deformed radiation resistance sheet contactsanother adjacent radiation resistance sheet or the conductive resistancesheet 60, direct heat conduction occurs, and therefore, loss of heatinsulation occurs. Therefore, the first radiation resistance sheet 321may extend not to reach the center of the conductive resistance sheet 60even when a predetermined deformation occurs in the first radiationresistance sheet 321. Since it is less likely that the second radiationresistance sheet 322 will contact the conductive resistance sheet 60,the second radiation resistance sheet 322 may extend further outward bypassing through the center of the conductive resistance sheet 60.

However, since it is likely that the second radiation resistance sheet322 will contact another adjacent radiation resistance sheet, a lengthof the second radiation resistance sheet 322 extending from the firstbar 311 is preferably limited to 10 to 15 mm when the radiationresistance sheet is an aluminum sheet having a thickness of 0.3 to 0.4mm. The third radiation resistance sheet 323 may extend outward by w1 ascompared with the second radiation resistance sheet 322. This is becausethe third radiation resistance sheet 323 is supported by the secondsupport plate 352.

In FIG. 5, it is illustrated that the radiation resistance sheet 32 doesnot extend inside the second vacuum space part 502. However, the presentdisclosure is not limited thereto, and the third radiation resistancesheet 323 of which at least one portion is provided to contact thesecond support plate 352 may extend up to the inside of the secondvacuum space part 502, thereby reducing radiation conduction heat.

A mounting end part (or side surface) 101 is provided at a corner of thefirst plate member 10, and a rib 102 is provided in the supporting unit30. As the mounting end part 101 is guided by the rib 102, the firstplate member 10 and the supporting unit 30 can be placed at accuratepositions, respectively. Thus, it is possible to improve fasteningaccuracy between parts.

Since the radiation resistance sheet 32 is provided as the thin plate,deformation may easily occur in the radiation resistance sheet 32 due toan external impact. Also, when the radiation resistance sheet 32 is notsupported by a predetermined distance, deformation may occur in theradiation resistance sheet 32 due to an external impact and a self load.If the radiation resistance sheet 32 is deformed, another part contactsthe radiation resistance sheet 32, and hence, the adiabatic effect maybe reduced. Therefore, when a radiation resistance sheet is provided, itis sufficiently considered not only that the radiation resistance sheetcan sufficiently resist radiation heat but also that the above-describeddeformation does not occur.

FIG. 6 is view showing a state in which the radiation resistance sheetis fastened to the supporting unit of FIG. 5. Referring to FIG. 6, asbars 31 are inserted into holes 38 provided in the radiation resistancesheet 32, respectively, the radiation resistance sheet 32 can be placedinside the vacuum space part 50. The holes 38 and the bars 31 areprovided at a predetermined distance. Some of the bars 31 are providedto perform a function of actually fixing the radiation resistance sheet32 and, simultaneously, to maintain the gap of the vacuum space part 50.

In other words, when the bars 31 extend to maintain the distance betweenthe plate members, the bars 31 pass through the radiation resistancesheet 32. At this time, the holes 38 are also to be provided to allowthe bars 31 not to interfere with the radiation resistance sheet 32.Here, bars 31 may be integrally provided to a support plate 35.

The radiation resistance sheet 32 may be provided in at least two,preferably, three or more so as to perform an action of sufficientradiation resistance. In order to sufficiently derive the effect ofradiation resistance using the plurality of radiation resistance sheets321, 322, and 323, the radiation resistance sheets are preferablylocated such that the internal gap of the vacuum space part can beequally divided. In other words, the radiation resistance sheets arepreferably located such that gaps between the radiation resistancesheets can be sufficiently maintained. To this end, gap blocks 36 (seeFIG. 7) may be provided to maintain gaps between the plate members 10and 20 and the radiation resistance sheets and gaps between theradiation resistance sheets.

A mounting rib 384 may be provided to perform coupling between thesupport plates or coupling between the supporting unit and the firstplate member 10. In addition, an insertion groove 383 is provided at anedge portion of the radiation resistance sheet 32 such that the mountingrib 384 does not interfere with the radiation resistance sheet 32. Sincethe mounting rib 384 is inserted through the insertion groove 383, theradiation resistance sheet 32 can extend further outward, and can morestably resist radiation heat transfer.

FIG. 7 is a sectional view taken along line I-I′ of FIG. 6. FIG. 8 is asectional view taken along line II-II′ of FIG. 6. Here, FIG. 7 is asectional view showing first holes 382 through which the bar 31 passesto support the radiation resistance sheet 32 and surroundings of thefirst holes 382, and FIG. 8 is a sectional view showing second holes 381through which the bar 31 passes without supporting the radiationresistance sheet 32 and surroundings of the second holes 382.

Referring to FIG. 7, the plurality of radiation resistance sheets 321,322, and 323 provided in the first holes 382 and the bar 31 passingthrough the first holes 382 are illustrated. In addition, gap blocks361, 362, and 363 are provided to maintain gaps between the radiationresistance sheets and gaps between the radiation resistance sheets andthe support plate 35. The first hole 382 may be provided to have adiameter to an extent where only a predetermined assembly tolerance isincluded in the diameter of the bar 31 such that the position of theradiation resistance sheets can be guided with respect to the bar 31.

When the first hole 382 is extremely small, it is difficult to put theradiation resistance sheet 32 into the bar 31, and hence the thinradiation resistance sheet 32 is frequently damaged. Therefore, thediameter of the first hole 382 is to be provided by further reflecting alength longer than the assembly tolerance. On the other hand, when thefirst hole 382 is extremely large, vibration is generated even in astate in which the radiation resistance sheet 32 is supported by the bar31, and hence the radiation resistance sheet 32 may be deformed.

Therefore, the diameter of the first hole 382 is preferably provided byfurther reflecting a length of only the assembly tolerance. Under suchcircumferences, the present inventor has found that the assemblytolerance is preferably provided as 0.1 to 0.5 mm. In FIG. 7, it may beconsidered that a value obtained by adding two W3 s at both sides aboutthe bar 31 is the assembly tolerance.

Meanwhile, the first hole 382 is preferably disposed such that anyportion of the radiation resistance sheet 32 does not contact the bar31. This is because, if the radiation resistance sheet 32 contacts thebar 31, heat conduction occurs, and therefore, the adiabatic effect isreduced.

Referring to FIG. 8, the plurality of radiation resistance sheets 321,322, and 323 provided in the second holes 381 and the bar 31 passingthrough the second holes 381 are illustrated. When the second hole 381is extremely small, the radiation resistance sheet 32 contacts the bar31, and therefore, adiabatic loss may be caused. When the second hole381 is extremely large, loss of radiation heat may occur through a gappart between the bar 31 and the second hole 381. Under suchcircumferences, the present inventor has found that a sum of both gapsbetween the second hole 381 and the bar 31 is preferably provided as 0.3to 1.5 mm.

In FIG. 8, a value obtained by adding two W4 s at both sides about thebar 31 may correspond to 0.3 to 1.5 mm. Meanwhile, the gap block 36 isprovided to be larger than both of the holes 381 and 382, so that thegap maintenance action of the radiation resistance sheet 32 can beperformed without any problem.

FIG. 9 is a plan view of one vertex portion of the radiation resistancesheet of FIG. 5. Referring to FIG. 9, the first holes 382 having a smalldiameter and the second holes 381 having a larger diameter than thefirst holes 382 are machined in the radiation resistance sheet 32. Ithas already been described that the holes 381 and 382 have a function ofallowing the bar 31 to pass therethrough and a function of supportingthe radiation resistance sheet.

The first holes 382 are preferably provided as dense as possible so asto prevent vibration of the radiation resistance sheet 32. However, asthe number of the first holes 382 is increased, a portion at which thebar 31 and the radiation resistance sheet 32 contact each other or areadjacent to each other is increased, and hence adiabatic performance maybe degraded. By considering the above-described two conditions, thedistance between the first holes 382 does not preferably exceed amaximum of 200 mm when the radiation resistance sheet 32 is an aluminumfoil having a thickness of 0.3 mm. When the section of the door 3 isprovided in a curved shape, the radiation resistance sheet 32 is alsoprovided in a curved shape. Hence, it is required to further maintainthe distance between the first holes 382 so as to avoid contact betweenthe radiation resistance sheets.

Under such a background, the distance between the first holes 382, whichis indicated by W5, does not preferably exceed a maximum of 200 mm. Inaddition, the first holes 382 are preferably provided an outermostportion from the center of the radiation resistance sheet 32 and avertex portion of the radiation resistance sheet 32. This is for thepurpose to prevent the degradation of the adiabatic performance, causedby contact between the radiation resistance sheet 32 and the bar 31, andto prevent the degradation of the adiabatic performance by allowing theradiation resistance sheet 32 to extend as outward as possible.

In addition, three second holes 381 may be provided between a pair offirst holes 382 adjacent to each other. In any one radiation resistancesheet, a number of the first holes 382 is more preferably smaller thanthat of the second holes 381 so as to prevent the degradation of theadiabatic performance.

Hereinafter, a vacuum pressure preferably determined depending on aninternal state of the vacuum adiabatic body will be described. Asalready described above, a vacuum pressure is to be maintained insidethe vacuum adiabatic body so as to reduce heat transfer. At this time,it will be easily expected that the vacuum pressure is preferablymaintained as low as possible so as to reduce the heat transfer.

The vacuum space part 50 may resist the heat transfer by applying onlythe supporting unit 30. Alternatively, the porous material 33 may befilled together with the supporting unit in the vacuum space part 50 toresist the heat transfer. Alternatively, the vacuum space part mayresist the heat transfer not by applying the supporting unit but byapplying the porous material 33.

The case where only the supporting unit is applied will be described.FIG. 10 illustrates graphs showing changes in adiabatic performance andchanges in gas conductivity with respect to vacuum pressures by applyinga simulation. Referring to FIG. 10, it can be seen that, as the vacuumpressure is decreased, i.e., as the vacuum degree is increased, a heatload in the case of only the main body (Graph 1) or in the case wherethe main body and the door are joined together (Graph 2) is decreased ascompared with that in the case of the typical product formed by foamingpolyurethane, thereby improving the adiabatic performance. However, itcan be seen that the degree of improvement of the adiabatic performanceis gradually lowered. Also, it can be seen that, as the vacuum pressureis decreased, the gas conductivity (Graph 3) is decreased.

However, it can be seen that, although the vacuum pressure is decreased,the ratio at which the adiabatic performance and the gas conductivityare improved is gradually lowered. Therefore, it is preferable that thevacuum pressure is decreased as low as possible. However, it takes longtime to obtain excessive vacuum pressure, and much cost is consumed dueto excessive use of a getter. In the embodiment, an optimal vacuumpressure is proposed from the above-described point of view.

FIG. 11 illustrates graphs obtained by observing, over time andpressure, a process of exhausting the interior of the vacuum adiabaticbody when the supporting unit is used. Referring to FIG. 11, in order tocreate the vacuum space part 50 to be in the vacuum state, a gas in thevacuum space part 50 is exhausted by a vacuum pump while evaporating alatent gas remaining in the parts of the vacuum space part 50 throughbaking. However, if the vacuum pressure reaches a certain level or more,there exists a point at which the level of the vacuum pressure is notincreased any more (Δt1).

After that, the getter is activated by disconnecting the vacuum spacepart 50 from the vacuum pump and applying heat to the vacuum space part50 (Δt2). If the getter is activated, the pressure in the vacuum spacepart 50 is decreased for a certain period of time, but then normalizedto maintain a vacuum pressure of a certain level. The vacuum pressurethat maintains the certain level after the activation of the getter isapproximately 1.8×10{circumflex over ( )}(−6) Torr. In the embodiment, apoint at which the vacuum pressure is not substantially decreased anymore even though the gas is exhausted by operating the vacuum pump isset to the lowest limit of the vacuum pressure used in the vacuumadiabatic body, thereby setting the minimum internal pressure of thevacuum space part 50 to 1.8×10{circumflex over ( )}(−6) Torr.

FIG. 12 illustrates graphs obtained by comparing vacuum pressures andgas conductivities. Referring to FIG. 12, gas conductivities withrespect to vacuum pressures depending on sizes of a gap in the vacuumspace part 50 are represented as graphs of effective heat transfercoefficients (eK). Effective heat transfer coefficients (eK) weremeasured when the gap in the vacuum space part 50 has three sizes of2.76 mm, 6.5 mm, and 12.5 mm.

The gap in the vacuum space part 50 is defined as follows. When theradiation resistance sheet 32 exists inside vacuum space part 50, thegap is a distance between the radiation resistance sheet 32 and theplate member adjacent thereto. When the radiation resistance sheet 32does not exist inside vacuum space part 50, the gap is a distancebetween the first and second plate members.

It can be seen that, since the size of the gap is small at a pointcorresponding to a typical effective heat transfer coefficient of 0.0196W/mK, which is provided to an adiabatic material formed by foamingpolyurethane, the vacuum pressure is 2.65×10{circumflex over ( )}(−1)Torr even when the size of the gap is 2.76 mm. Meanwhile, it can be seenthat the point at which reduction in adiabatic effect caused by gasconduction heat is saturated even though the vacuum pressure isdecreased is a point at which the vacuum pressure is approximately4.5×10{circumflex over ( )}(−3) Torr. The vacuum pressure of4.5×10{circumflex over ( )}(−3) Torr can be defined as the point atwhich the reduction in adiabatic effect caused by gas conduction heat issaturated. Also, when the effective heat transfer coefficient is 0.1W/mK, the vacuum pressure is 1.2×10{circumflex over ( )}(−2) Torr.

When the vacuum space part 50 is not provided with the supporting unitbut provided with the porous material, the size of the gap ranges from afew micrometers to a few hundredths of micrometers. In this case, theamount of radiation heat transfer is small due to the porous materialeven when the vacuum pressure is relatively high, i.e., when the vacuumdegree is low. Therefore, an appropriate vacuum pump is used to adjustthe vacuum pressure. The vacuum pressure appropriate to thecorresponding vacuum pump is approximately 2.0×10{circumflex over( )}(−4) Torr.

Also, the vacuum pressure at the point at which the reduction inadiabatic effect caused by gas conduction heat is saturated isapproximately 4.7×10{circumflex over ( )}(−2) Torr. Also, the pressurewhere the reduction in adiabatic effect caused by gas conduction heatreaches the typical effective heat transfer coefficient of 0.0196 W/mKis 730 Torr. When the supporting unit and the porous material areprovided together in the vacuum space part, a vacuum pressure may becreated and used, which is middle between the vacuum pressure when onlythe supporting unit is used and the vacuum pressure when only the porousmaterial is used.

The vacuum adiabatic body proposed in the present disclosure may bepreferably applied to refrigerators. However, the application of thevacuum adiabatic body is not limited to the refrigerators, and may beapplied in various apparatuses such as cryogenic refrigeratingapparatuses, heating apparatuses, and ventilation apparatuses.

Hereinafter, a vacuum adiabatic body according to a third embodimentwill be described.

FIG. 13 is a view illustrating a correlation between a supporting unitand a first plate member of a vacuum adiabatic body according to a thirdembodiment, which shows any one edge portion. FIG. 14 is an enlargedview of FIG. 13. FIG. 15 is a longitudinal sectional view of FIG. 13.

Referring to FIGS. 13 to 15, the vacuum adiabatic body according to theembodiment includes a first plate member (or first plate) 110 providinga wall for a low-temperature space, a second plate member (or secondplate) 120 providing a wall for a high-temperature space, and a vacuumspace part (or vacuum space) 150 defined as a gap part between the firstand second plate members 110 and 120, and a supporting unit (or support)130 for reducing deformation of the vacuum space part 150.

The supporting unit 130 may include a plurality of bars 131 interposedbetween the first and second plate members 110 and 120, a first supportplate 135 provided at one ends of the plurality of bars 131, and asecond support plate 136 provided at the other ends of the plurality ofbars 131.

For pitches between the plurality of bars 131, a pitch at a portionadjacent to an edge portion of the first plate member 110 or an edgeportion of the second plate member 120 may be formed narrower than thoseof the other portions. This is because the supporting ability of theedge portion of each of the first and second plate members 110 and 120is weak as compared with the other portions.

The first support plate 135 may be disposed to contact the first platemember 110, and the second support plate 136 may be disposed to contactthe second plate member 120. Each of the first and second support plates135 and 136 may be provided in a grid shape. Accordingly, the area ofeach of the first and second support plates 135 and 136 respectivelycontacting the first and second plate members 110 and 120 is decreased,thereby reducing a heat transfer amount.

Extending parts (or extension tabs) 112 for reinforcing the supportingability of the first plate member 110 with the supporting unit 130 maybe formed at the first plate member 110. The extending parts 112 may beformed to extend downward from an end portion of the first plate member110.

Fixing parts (or fixing brackets) 137 and 138 may be formed at thesecond support plate 136. At least one portion of each of the fixingparts 137 and 138 may contact the extending part 112.

The extending part 112 may be provided in plurality, and the fixingparts 137 and 138 may be formed to correspond to the respectiveextending parts 112. The fixing parts 137 and 138 may include a firstfixing part (or first fixing bracket) 137 contacting one surface of theextending part 112.

The first fixing part 137 may be formed to extend upward from the secondsupport plate 136. Meanwhile, in these figures, the first fixing part137 is disposed at the outside of the extending part 112. Alternatively,the first fixing part 137 may be provided at the inside of the extendingpart 112.

The fixing parts 137 and 138 may include a second fixing part (or secondfixing bracket) 138 surrounding the extending part 112. The secondfixing part 138 may be formed to extend upward from the second supportplate 136. A groove into which the extending part 112 is inserted may beformed in the second support plate 136. Accordingly, the extending part112 can be coupled to the second fixing part 138.

As shown in FIG. 13, the first fixing parts 137 may be arranged in a rowat one side of the second support plate 136, and the second fixing parts138 may be arranged in a row at another side of the second support plate136. However, the present disclosure is not limited to theabove-described arrangement.

The vacuum adiabatic body further includes a conductive resistance sheet160 for preventing heat conduction between the first and second platemembers 110 and 120. The conductive resistance sheet 160 may includesealing parts (or seals) 161 at which both ends of the conductiveresistance sheet 160 are sealed so as to define at least one portion ofa wall for the vacuum space part 150 and to maintain the vacuum state.The conductive resistance sheet 160 may be provided as a thin foil inunit of micrometers so as to reduce the amount of heat conductionflowing along the wall for the vacuum space part 150.

A side frame 170 may be provided at an outside of the conductiveresistance sheet 160. One side of the conductive resistance sheet 160may be fastened to the first plate member 110, and the other side of theconductive resistance sheet 160 may be fastened to the side frame 170.

A plurality of bars 131 for maintaining a distance between the sideframe 170 and the second plate member 120 may be interposed between theside frame 170 and the second plate member 120. The shortest distancebetween a bar disposed at an outermost portion and a plurality of barsinterposed between the side frame 170 and the second plate members 120among the plurality of bars 131 interposed between the first and secondplate members 110 and 120 is shorter than a pitch between the pluralityof bars 131 interposed between the first and second plate members 110and 120. This is for the purpose to prevent deformation of the sideframe 170.

Welding parts as the sealing parts 161 may be formed at the conductiveresistance sheet 160. Specifically, both the sides of the conductiveresistance sheet 160 may be respectively mounted on the first platemember 110 and the side frame 170 and then welded.

FIG. 16 is a view showing the supporting unit and the radiationresistance sheet of FIG. 13. FIG. 17 is a plan view of FIG. 16.Referring to FIGS. 16 and 17, the supporting unit 130 may be mounted onthe second plate member 120. The supporting unit 130 may include aplurality of radiation resistance sheets 132, 133, and 134.

The plurality of radiation resistance sheets 132, 133, and 134 may bepenetrated by a plurality of bars 131. The radiation resistance sheets132, 133, and 134 may be disposed to be spaced apart from each other bya separate spacing member.

First and second fixing parts 137 and 138 protruding upward are providedto the second support plate 136. The plurality of radiation resistancesheets 132, 133, and 134 are disposed over a range as wide as possiblewithin the vacuum space part 150, which is effective in terms ofadiabatic performance. However, if the first and second fixing parts 137and 138 contact the plurality of radiation resistance sheets 132, 133,and 134, the adiabatic performance may be degraded by heat transfer.

Therefore, the first and second fixing parts 137 and 138 are to bedisposed so as not to contact the plurality of radiation resistancesheets 132, 133, and 134. Thus, a depression part (or notch) 132 a inwhich the first fixing part 13 can be accommodated is formed in a firstradiation resistance sheet 132. A depression part 132 b in which thesecond fixing part 138 can be accommodated is formed in the firstradiation resistance sheet 132. Accordingly, the first and second fixingparts 137 and 138 cannot contact the first radiation resistance sheet.Depression parts in which the first and second fixing parts 137 and 138are accommodated may also be formed in second and third radiationresistance sheets 133 and 134.

FIG. 18 is a view showing a vacuum adiabatic body according to a fourthembodiment. FIG. 19 is a view showing a first plate member of FIG. 18.

Referring to FIGS. 18 and 19, unlike the aforementioned embodiment, thevacuum adiabatic body of this embodiment is not provided with any fixingpart, and includes an extending part having a different shape.

The vacuum adiabatic body of this embodiment includes a first platemember (or first plate) 210 and a second plate member (or second plate)220. A first support plate 235 contacts the first plate member 210, anda second support plate 236 contacts the second plate member 220. Atleast one bar 231 may be interposed between the first and second supportplates 235 and 236.

At least one radiation resistance sheet 232 may be provided between thefirst and second support plates 235 and 236. The radiation resistancesheet 232 may be penetrated by the at least one bar 231. An extendingpart (or extension bracket) 212 extending downward may be provided tothe first plate member 210. The extending part 212 may be provided inplurality.

The extending part 212 may contact a side of the first support plate235. As the extending part 212 is provided in plurality, the first platemember 210 may be fixed to the first support plate 235. In thesefigures, it can be seen that the first support plate 235 is insertedinto the first plate member 210 through the extending part 212.

A lower end portion of the extending part 212 may be located above theradiation resistance sheet 232 such that the extending part 212 does notcontact the radiation resistance sheet 232. The extending part 212 maybe integrally formed with the first plate member 210. However, thepresent disclosure is not limited thereto, and the extending part 212and the first plate member 210 may be provided as separate componentsfrom each other.

FIG. 20 is a view showing a vacuum adiabatic body according to a fifthembodiment. Referring to FIG. 20, the vacuum adiabatic body of thisembodiment is different from that of the aforementioned embodiment inonly the shape of an extending part.

Specifically, the vacuum adiabatic body of this embodiment includes anextending part (or extension bracket) 312 extending downward from anedge portion of a first plate member 310. A first support plate 335contacts a lower end of the first plate member (or first plate) 310, andthe extending part 312 may be provided to contact the first supportplate 335.

The extending part 312 may be provided to extend downward from theentire edge portion of the first plate member 310. That is, theextending part 312 may be formed longer than the extending part 212 ofthe aforementioned embodiment. In this case, only one extending part 312is provided at one corner of the first plate member 310.

The extending part 312 may be integrally formed with the first platemember 310. However, the present disclosure is not limited thereto, andthe extending part 312 and the first plate member 310 may be provided asseparate components from each other.

The extending part 312 may extend downward within a length range whereit does not contact a radiation resistance sheet. Accordingly, the firstplate member 310 can be supported by being fixed to the first supportplate 335.

FIG. 21 is a view showing a vacuum adiabatic body according to a sixthembodiment. FIG. 22 is a longitudinal sectional view of FIG. 21.

Referring to FIGS. 21 and 22, in the vacuum adiabatic body of thisembodiment, an extending part may be formed to protrude downward from asurface of a plate member instead of an edge portion of the platemember.

The vacuum adiabatic body of this embodiment includes a first platemember (or first plate) 410, a first support plate 435 contacting alower portion of the first plate member 410, and at least one bar 431supporting the first support plate 435. The at least one bar 431 may bebetween the first support plate 435 and a second support plate 436.

An extending part (or recess) 412 protruding toward the first supportplate 435 may be formed in the first plate member 410. Unlike theextending part of the aforementioned embodiment, the extending part 412is formed to protrude downward from any one place of the first platemember 410 instead of an edge portion of the first plate member 410.

The extending part 412 may be formed in the planar first plate member410 using a forming mold. The extending part 412 may be formed toprotrude in a shape corresponding to a groove provided in the firstsupport plate 435. Thus, the extending part 412 can be inserted into thegroove provided in the first support plate 435.

Accordingly, the first support plate 435 can be supported by being fixedto the first support plate 435. Meanwhile, in the present disclosure, ithas been described that the first plate member is fixed to thesupporting unit. However, instead of the first plate member, the secondplate member may be fixed to the supporting unit.

FIG. 23 is a view showing a vacuum adiabatic body according to a seventhembodiment. Referring to FIG. 23, the vacuum adiabatic body according tothe seventh embodiment includes a first plate member (or first plate)1110, a second plate member (or second plate) 1120, and a supportingunit (or support) 1130. The supporting unit 1130 includes a firstsupport plate 1135, a second support plate 1136, at least one bar 1131,and a radiation resistance sheet 1132.

The first support plate 1135 may contact the first plate member 1110,and the second support plate 1136 may contact the second plate member1120. Here, each of the first plate member 1110, the second plate member1120, the first support plate 1135, the second support plate 1136, andthe radiation resistance sheet 1132 is formed as a curved surface, andhas a larger curvature as it is more distant from the center ofcurvature.

FIG. 24 is a view showing the supporting unit of FIG. 23. FIG. 25 is anexploded view of the supporting unit of FIG. 23. Referring to FIGS. 24and 25, the supporting unit 1130 includes a first support plate 1135, asecond support plate 1136, and a plurality of bars 1131.

The supporting unit 1130 may be formed into a structure in which theplurality of bars 1131 are fixed to the second support plate 1136, andthe first support plate 1135 is attachable/detachable to/from the otherends of the plurality of bars 1131. Therefore, an assembly of the secondsupport plate 1136 and the plurality of bars 1131 may be referred to asa “base,” and the first support plate 1135 may be referred to as a“cover.”

The first support plate 1135 may be provided with a plurality ofinsertion parts or holes 1137 into which the respective bars 1131 areinserted. A pitch between the plurality of insertion parts 1137 has asmall value as compared with that between the plurality of bars 1131attached to the second support plate 1136.

A distance R1 from the center of curvature to the first support plate1135, a distance R2 from the center of curvature to the radiationresistance sheet 1132, and a distance R3 from the center of curvature tothe second support plate 1136 are sequentially increased. Pitches P1,P2, and P3 between the plurality of bars 1131 are sequentially increasedas they are distant from the center of curvature. Here, P1 refers to apitch between the plurality of insertion parts 1137 provided in thefirst support plate 1135, P2 refers to a pitch between through-holesprovided in the radiation resistance sheet 1132, and P3 refers to apitch between spots at which the second support plate 1136 and theplurality of bars 1131 are connected to each other.

FIG. 26 is a view showing a case where a plurality of radiationresistance sheets is provided in the supporting unit of FIG. 23.Referring to FIG. 26, a plurality of radiation resistance sheets 1132,1133, and 1134 may be provided between the first and second supportplates 1135 and 1136. A first radiation resistance sheet 1132, a secondradiation resistance sheet 1133, and a third radiation resistance sheet1134 are sequentially disposed in a direction distant from the center ofcurvature.

A plurality of through-holes 1132 a, 1133 a, and 1134 a penetrated bythe bars 1131 may be formed in the radiation resistance sheets 1132,1133, and 1134, respectively.

Pitches between the plurality of through-holes 1132 a, 1133 a, and 1134a may be sequentially increased as they are distant from the center ofcurvature.

End portions of the plurality of radiation resistance sheets 1132, 1133,and 1134 may be lengthened as they are distant from the center ofcurvature. This can be considered in the same context as that thepitches between the plurality of through-holes 1132 a, 1133 a, and 1134a are increased.

FIG. 27 is a view showing the supporting unit of FIG. 23, viewed fromthe top. FIG. 28 is a view showing a side of the supporting unit of FIG.23. FIG. 29 is a view showing an edge portion of a support plate of FIG.23.

Referring to FIGS. 27 to 29, the second support plate 1136 includes aplurality of connection ribs 1136 a and 1136 b forming grid shapes. InFIG. 27, the plurality of connection ribs 1136 a and 1136 b include aplurality of first connection ribs 1136 a extending in the horizontal orfirst direction and a plurality of second connection ribs 1136 bextending in the vertical or second direction.

The plurality of first connection ribs 1136 a are formed to extend alongthe circumferential direction of the second support plate 1136 forming acurved surface, and the plurality of second connection ribs 1136 b areformed to extend along the direction of the center of curvature of thesecond support plate 1136. That is, the plurality of first connectionribs 1136 a are curved such that each of the plurality of firstconnection ribs 1136 a forms a curve, and each of the plurality ofsecond connection ribs 1136 b forms a straight line.

Each of the plurality of first connection ribs 1136 a may be formedthinner than each of the plurality of second connection ribs 1136 b.This is for the purpose that each of the plurality of first connectionribs 1136 a is well warped to form a curve. In this case, each of theplurality of second connection ribs 1136 b may be formed thicker thaneach of the plurality of first connection ribs 1136 a, therebyreinforcing its strength.

For example, the thickness of each of the plurality of first connectionribs 1136 a may be formed to be equal to or greater than 1 mm and equalto or smaller than 3 mm. Like the second support plate 1136, a pluralityof first connection ribs and a plurality of second connection ribs mayalso be provided in the first support plate 1135. Bars 1131 may berespectively provided at spots at which the first and second connectionribs 1136 a and 1136 b.

A plurality of connection parts (or connection bases) 1138 may be formedat portions at which the respective bars 1131 and the second supportplate 1136 meet. A pitch between the plurality of connection parts 1138may be formed larger than that between the plurality of insertion parts1137. This is because the plurality of connection parts 1138 is disposedmore distant from the center of curvature than the plurality ofinsertion parts 1137.

However, the plurality of connection parts 1138 are provided to thefirst support plate 1135, and the plurality of insertion parts 1137 areprovided in the second support plate 1136, a pitch between the pluralityof connection parts 1138 may be formed smaller than that between theplurality of insertion parts 1137. This is because the plurality ofconnection parts 1138 is disposed closer to the center of curvature thanthe plurality of insertion parts 1137.

Each of the plurality of connection parts 1138 may be formed to berounded. Accordingly, it is possible to reduce damage caused by a frontend in machining or assembling of the second support plate 1136. A roundsize R may be approximately 0.05 mm to 1 mm.

A third connection rib 1139 formed at the edge portion of the secondsupport plate 1136 is formed thicker than the first and secondconnection ribs 1136 a and 1136 b. For example, the third connection rib1139 may be formed thicker by about 0.2 mm than the first and secondconnection ribs 1136 a and 1136 b.

Also, the third connection rib 1139 may be made of a material having alarger density than the first and second connection ribs 1136 a and 1136b. This is for the purpose to complement strength because the edgeportion of the second support plate 1136 may be weak in terms ofstrength. Accordingly, it is possible to prevent damage of the secondsupport plate 1136.

According to the present disclosure, the vacuum adiabatic body can beindustrially applied to various adiabatic apparatuses. The adiabaticeffect can be enhanced, so that it is possible to improve energy useefficiency and to increase the effective volume of an apparatus.

The invention claimed is:
 1. A vacuum adiabatic body comprising: a firstplate defining at least one portion of a first side of a wall adjacentto a first space having a first temperature; a second plate defining atleast one portion of a second side of the wall adjacent to a secondspace having a second temperature different from the first temperature;a seal that seals the first plate and the second plate to provide athird space that has a third temperature between the first temperatureand the second temperature and is in a vacuum state; a support thatsupports the first and second plates and is provided in the third space;and an exhaust port through which a gas in the third space is exhausted,wherein the first plate includes an extension tab that extends into thethird space to be coupled to the support such that the coupling of theextension tab and the support reinforces the supporting ability of thefirst plate with the support, and the extension tab extends downwardfrom an edge of the first plate.
 2. The vacuum adiabatic body accordingto claim 1, further including a conductive resistance sheet connected toat least one of the first and second plates.
 3. The vacuum adiabaticbody according to claim 2, wherein the support includes a fixing bracketcontacting at least one surface of the extension tab to support thefirst plate.
 4. The vacuum adiabatic body according to claim 2, whereinthe support includes a fixing bracket surrounding the extension tab tosupport the first plate.
 5. The vacuum adiabatic body according to claim3, further including at least one radiation resistance sheet formed in aplate shape provided in the third space, wherein the radiationresistance sheet includes a notch corresponding to the fixing bracket.6. The vacuum adiabatic body according to claim 1, wherein the supportincludes a support plate extending in a direction parallel to the firstplate, the support plate being coupled to the extension tab.
 7. Thevacuum adiabatic body according to claim 6, wherein the extension tabcovers an edge of the support plate.
 8. The vacuum adiabatic bodyaccording to claim 1, further including a radiation resistance sheetthat limits radiation heat transfer between the first and second plates,wherein the radiation resistance sheet is provided in a plate shapeinside the third space, and a bottom end of the extension tab is spacedapart from the radiation resistance sheet.
 9. A refrigerator comprising:a main body including an internal space in which goods are stored; and adoor provided to open and close the main body, wherein at least one ofthe main body and the door includes the vacuum adiabatic body ofclaim
 1. 10. A refrigerator comprising: a main body including aninternal space in which goods are stored; and a door provided to openand close the main body, wherein, in order to supply a refrigerant intothe main body, the refrigerator includes: a compressor that compressesthe refrigerant; a condenser that condenses the compressed refrigerant;an expander that expands the condensed refrigerant; and an evaporatorthat evaporates the expanded refrigerant to transfer heat, wherein atleast one of the main body and the door includes a vacuum adiabaticbody, wherein the vacuum adiabatic body includes: a first plate definingat least one portion of a first side of a wall adjacent to the internalspace having a first temperature; a second plate defining at least oneportion of a second side of the wall adjacent to an external spacehaving a second temperature different from the first temperature; a sealthat seals the first plate and the second plate to provide a vacuumspace that has a third temperature between the first temperature and thesecond temperature and is in a vacuum state; a support that supports thefirst and second plates and is provided in the vacuum space; and anexhaust port through which a gas in the vacuum space is exhausted,wherein the first plate is provided with an extension tab that extendstoward the vacuum space, the extension tab being coupled to the supportsuch that the coupling of the extension tab and the support reinforcesthe supporting ability of the first plate with the support, and theextension tab extends downward from an edge of the first plate.